Three seat-side servers at Yankee Stadium filed suit yesterday over claims they’re being cheated out of the 20 percent service charge tacked onto their customers’ bills.

Plaintiffs Evelyn Ryan, David Carr and Tujuan Garner say they don’t even get a taste of the mandatory mark-up that concessionaire Legends Hospitality — partly owned by the Bronx Bombers — adds for delivery of its $9.50 beers and $8.50 hot dogs.

“It’s nerve-racking, because people would question if we get the 20 percent,” said Ryan, 36, of Washington Heights.

“All we’re allowed to say is, ‘Additional gratuity is at your discretion.’ They wonder where it’s going if it’s not going to you.”

Defendants include both Legends — which was founded in advance of the 2009 opening of the new Yankee Stadium — and former concessionaire Centerplate.

A Legends spokeswoman said, “All of our employees are paid properly and in accordance with their union contract.”

Centerplate declined to comment.

A representative for Local 153 of the Office and Professional Employees International Union didn’t return a call for comment.